High Quality Content by WIKIPEDIA articles! HMS Raider (P275) is an Archer class patrol and training vessel of the British Royal Navy, used to fulfil the sea-training syllabus of the Bristol University Royal Naval Unit (Bristol URNU). Based in Devonport, HMS Raider is used to conduct sea-training at weekends during term-time; travelling to ports on the south coast and on the continent. During the Easter and Summer vacations, HMS Raider is deployed for up to 6 weeks of sea time.